How to fix This Seam in Fork
your topology has many errors:

red circle: you have 5 edges come from a single vertex
green circle: you have 3 edges come from a single vertex

You need to have only quads (A square or rectangular polygon is referred to as a quad or quadrilateral polygon, and is a four-sided polygon. It has exactly 4 vertices at the corners connected by 4 edges) for best shading results.
How to fix it?
Edit your topology to have only quads:

merge the vertex in orange circles. Select the vertices and press M (or Alt+M in version 2.79 or older)
remove the vertex in the yellow circle
continue fixing the topology to have only quads


here's a good topology for a fork (source here: https://www.turbosquid.com/3d-models/fork-metal-3d-model-1360722)